1. Field of the Invention
This invention relates to bearings used on garage door assemblies for example, for garage doors used on car washes, and the like, and in particular to bearings supporting the shaft at the top of a garage door assembly adjacent the sprocket and drive train for raising and lowering the garage door.
2. Description of the Related Art
Garage doors in car washes are exposed to heavy use, constant wetting, solvents and detergents, and extremes of temperature. There is generally a bearing at each end of the shaft supporting the drive train and associated hardware at the top of the garage door.
Typical bearings used for this purpose are made of galvanized steel or mild steel. An example of a bracket 18 in which prior bearings are typically mounted is shown in FIG. 1 and has a bracket hole 44 in which to mount a bearing and two mounting holes 45 into which the bolts to hold the bearing are inserted. An example of a prior bearing 10 used for garage door shafts is shown in FIGS. 2-3. In brief, the prior bearings 10 comprise an internal bearing portion 12, mounted in successive cylindrical portions 14, the outermost of which is mounted within an attachment portion 16. The prior bearing 10 is fastened to a mounting bracket 18 by means of two bolts 20 placed through the attachment portion 16 and the bracket 18. Holes 24 in bracket 18 are for attaching the bracket to the track in which the garage door slides, and holes 26 are for attaching the bracket to a wall. Various adjustment means 22 are provided to optimize the bearing internal size. Bearings now used often have rust problems due to the constant wetting, as the mild steel rusts and/or the galvanized coating wears off the bearing. The bearings that are used in many of these roller assemblies tend to seize, particularly under the conditions of humidity and temperature present in a car wash, whether or not the bearings are sealed bearings. These bearings are also complicated to manufacture and install because of their many components.
The installation of the entire garage door must be accurate so that the door is not other than exactly vertical and so that the sprocket/drive train assembly is spaced at a sufficient distance from the door and the bearing is a sufficient distance from the pick-up drum for the cable that takes the door upward, so that when the door is raised and lowered no part of the assembly catches on another part where it should not, and so that the moving chain moves parallel to the side of the door. For this purpose, either the person doing the installation must be very careful in making measurements, or some type of spacer must be placed between the bracket which holds the bearing and both the sprocket/chain assembly and the pick-up drum.
It is therefore an object of the invention to provide a shaft bearing usable on garage doors for car washes which is rust-resistant and is in a singe piece.
It is a further object of the invention to provide a bearing which also serves as a spacer to reduce the need for exacting measurement during installation and eliminates the need for a separate spacer.
Other objects and advantages will be more fully apparent from the following disclosure and appended claims.